DNA and Protein Synthesis

Nucleic Acids

Nucleic Acids - Function

• Control the processes of heredity by which cells and organisms reproduce proteins.

Nucleic Acids – Types

• DNA–Deoxyribonucleic Acid

• RNA–Ribonucleic Acid

Do you remember DNA structure?

SUGAR

Phosphate

Let’s build on that knowledge…

DNA is …

Single

stran

ded

Double st

randed

Triple

stran

ded

0% 0%

100%1. Single stranded2. Double stranded3. Triple stranded

Every nucleotide is made up of…

Sugar

Phosphate

Nitrogen

base

All of th

e above

0%

100%

0%0%

1. Sugar2. Phosphate3. Nitrogen base4. All of the above

The two strands of DNA are bonded together in the middle by their…

Sugars

Phosphate

s

Nitrogen

base

s

0%

95%

5%

1. Sugars2. Phosphates 3. Nitrogen bases

Protein Synthesis

• It’s a process– DNA -> RNA -> Amino Acids (Protein)

RNA

• Sugar is Ribose NOT what…• Has nitrogen base Uracil

instead of Thymine– Also contains the other 3

bases…what are they?• Only single stranded

RNA

Three processes in this unit…

• 1. Replication (DNA DNA)• 2. Transcription (DNA mRNA)• 3. Translation (RNA Protein)

Let’s Build A Protein

Transcription

• 1.) DNA strand unzips– The bonds between the nitrogen bases are broken– Initiated by RNA polymerase (enzyme) binding to

promoter site on DNA• 2.) A single strand of mRNA (messenger RNA) is

made– Pair up the bases

The mRNA then travels from nucleus to cytoplasm

Transcription

Where in the cell does transcription take place?

Cytoplas

m

Mito

chond

ria

Nucleus

Golgi B

ody

Vacuole

9%0% 0%0%

91%1. Cytoplasm2. Mitochondria3. Nucleus4. Golgi Body5. Vacuole

Any given segment of DNA has directions that make unique what?

Gluco

se

Protei

ns

Lipids

Blood cells

0% 5%0%

95%1. Glucose2. Proteins3. Lipids4. Blood cells

If a DNA strand has the following sequence of base pairs – A C T G G T C C A A , then the mRNA strand would have what sequence?

T G A C

C A

G G

T T

A C T G

G T C

C A

A

T G U C

C U

G G

T T

U G A

C C

A G

G U

U

24%

67%

10%0%

1. T G A C C A G G T T2. A C T G G T C C A A3. T G U C C U G G T T4. U G A C C A G G U U

Why is mRNA called messenger RNA?

• Because it carries the directions to make a protein to the ribosome like a message

Actually 3 types of RNA

• mRNA- messenger – Brings message from nucleus to ribosomes in

cytoplasm• rRNA- ribosomal

– Make up a ribosome• tRNA- transfer

– “transfers” amino acids from the cytoplasm to the ribosome to be added to the chain

The difference between RNA and DNA is what?

1. The phosphates2. The sugars3. The nitrogen bases4. The way the

monomer units bond

mRNA is synthesized in the nucleus and travels to the cytoplasm to meet up with which organelle?

1. Mitochondria2. Ribosome3. Golgi Body4. Lysosome5. Nucleus

Translation

• mRNA meets up with a ribosome…why??• tRNA molecules bring amino acids to ribosomes• An mRNA codon will pair with a tRNA anticodon

– Codon: 3 Nitrogen base sequence in mRNA that specifies a specific amino acid

– Anticodon: 3 Nitrogen base sequence in tRNA• As tRNA’s are added, amino acids are bonded together and

will be released as a fully functional protein.

Translation

That’s the process, Now how do you know what amino acids make up a particular protein

• We use an mRNA codon chart

Where in the cell does transcription, the first part of protein synthesis, take place?

Mito

chond

ria

Nucleus

Ribosomes

Cytoplas

m

0% 4%9%

87%1. Mitochondria2. Nucleus3. Ribosomes4. Cytoplasm

DNA has the directions to make what?

Gluco

se

Nucleotid

es

Protei

ns

Mono

sacc

harid

es

0% 0%

96%

4%

1. Glucose2. Nucleotides3. Proteins4. Monosaccharides

After a strand of mRNA is made where does it go?

Ribosome

Mito

chond

ria

Lysoso

me

Vacuole

94%

0%0%6%

1. Ribosome2. Mitochondria3. Lysosome4. Vacuole

Where in the cell does translation, the second part of protein synthesis, take place?

Mito

chond

ria

Nucleus

Golgi b

ody

Cytoplas

m

0%

95%

0%5%

1. Mitochondria2. Nucleus3. Golgi body4. Cytoplasm

Molecules called tRNA’s are floating around the cytoplasm carrying what?

mRNA’s

Gluco

se DNA

Nucleotid

es

Amino A

cids

19%

0%

71%

5%5%

1. mRNA’s2. Glucose3. DNA4. Nucleotides5. Amino Acids

An mRNA codon is made up of how many nitrogen bases?

1 3 6 24

14%5%5%

77%1. 12. 33. 64. 24

Using your mRNA codon chart, what amino acid would a ribosome call for if the codon was A A C ?

Phenyla

lanine

Glutam

ine

Aspara

gine

Lysine

Tyrosin

e

0% 0% 0%5%

95%1. Phenylalanine2. Glutamine3. Asparagine4. Lysine5. Tyrosine

What protein would be synthesized from the following mRNA strand?A C U U U C G A A U A C

Threonine –

phenyla

l...

Phenyla

lanine –

leuci.

.

Tyrosin

e – glutam

ate..

Lysine –

cyste

ine – a.

..

95%

0%0%5%

1. Threonine – phenylalanine – glutamate – tyrosine

2. Phenylalanine – leucine – methionine – valine

3. Tyrosine – glutamate – phenylalanine – threonine

4. Lysine – cysteine – arginine – histidine

What protein would be synthesized from the following DNA segment?T A A G T A C G C T A G

Isoleu

cine –

alan

ine –.

..

Isoleu

cine –

histidine .

..

Phenyla

lanine –

leuci.

.

Isoleu

cine –

leuc

ine –.

..

5% 5%0%

90%1. Isoleucine – alanine –

histidine – alanine 2. Isoleucine – histidine –

alanine – isoleucine 3. Phenylalanine – leucine –

valine – arginine 4. Isoleucine – leucine –

threonine – lysine

How would you assess your comprehension of DNA and Protein Synthesis?

A B C D

30%

0%

17%

52%1. A2. B3. C4. D